Centrifugal fan-wheel.



B. s. FOSS. GENTBIFUGAL FAN WHEEL.

APPLICATION FILED JAN. 28, 1911.

1,038,1 10, Patented Sept. 10, 1912.

mm ME? 5 mm mm UNITED STATES PATENT oFFIo BENJAMIN S. FOSS, OF BOSTON, MASSACHUSETTS, A SSIGNOB TO B. F. STURTEVANT COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

CENTBIFUGAL FAN-WHEEL.

Specification of Letters Patent. Patented sept. 10, 1912.

Application filed January 28, 1911. Serial No. 605,285.

' Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Centrifugal Fan-Wheels; and I do hereby declare the following to be a full,- clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention relates to that type of centrifugal fans in which the fan wheel is provided with a multiplicity of long narrow blades arranged in drum form.

It is the object of the invention to improve and simplify the construction of small fan wheels of this type so that wheels having the requisite strength and rigidity may be conveniently and economically manufactured. To this end the invention contemplates forming the blading and the end rings for supporting the blades by ing the metal connecting the blades andstrips, since a strong and more rigid con struction is thereby secured. This may be accom lished by staggering the longitudinal slits and extending them so that the end of, each slit is substantially in line transversely of the blank with the end of the succeeding slit, but separated therefrom.

by intervening metal which is given a straight transverse bend to bring the blade bounded by adjacent transverse slits into the desired angular relation to the end strips. While it is preferred to slit and bend aflat metal strip or sheet to form the blades and end strips, and thereafter bendthe blank into cylindrical form, it will be understood that a cylindrical blank may be slit and bent to form arallel'blades integrally connected wit 7 cylindrical end strips, without departing from the broader features of the invention. I

The invention consists in the features of construction and combination of parts hereinafter described and referred to in the claims, the advantages of which will be apparent to those skilled in theart from the following detailed'description.

The features of the invention will be readily understood from an inspection of the accompanying drawings, in which Figure 1 is a front end elevation of a fan wheel embodying the invention in its preferred form; Fig. 2 is a sectional view on line 22, Fig. 1; Fig. 3 is a plan view of a sheet metal blank slit and partially bent to form the construction of blades "indicated in Figs. 1 and 2; Fig. 4 is an end view of the blank shown in Fig. 3; Fig. 5 is a sectional view on line 5 5, Fig.3; Fig. 6 is a plan view showing the shape of the blank after the'loending and shaping of the blades has been completed; and Fig. 7 is a sec tional view on line 7-7, Fig 6.

In the construction of fan shown in the drawings the blading and supporting end strips are formed from a sheet or strip of sheet metal having a width corresponding to the length of the fan wheel to be made, and having a length slightly in excess of the circumference of the finished wheel. In forming the blades having the construction and arrangement illustrated in Fig. 1, the blank 1 is subjected to the action of dies which form the transverse slits 2 and the longitudinal or circumferential slits 3 lead! ing from the ends of the transverse slits within the edges of the blank.

blades 4.- lie wholly within the end rings or strips 5 and 6 so that the spaces between the blades are open at the entrance end of out of the plane of the marginal strips 5 In'the an I ran'gement of blading shown in Fig. 1, the

V as

and 6, as indicated in Fig. 5. Since the ends of the slits 3 are substantially in line transversely of the blank, the metal between the transverse slits 2 may be bent out 5 of the plane of the end strips by a directtransverse bend across the metal at 7. After the blank has been slit and partially bent, as indicated in Fig. 5, it is subjected to the action of another set at dies which give the blades the desired shape and angular arrangement with. relationto the end strips 5 and 6. in the construction shown the blades are concaved and are "orovided with transverse corrugations, aslndicated in Figs. 6 and 7. After the blading has been thus bent and shaped, the blank is bent into cylindrical form, and the ends of the blank overlapped and soldered or otherwise secured, as indicated at 8 in Fig. l. The drum thus formed may be secured to a supporting disk 9 which is provided. with a flange l fittingwithin the end strip 6, and with a hub "11 for securing the wheel to a shaft.

ln bending and shaping theblades only the metal between the transverseand longitudinal slits is bent and shaped,"'-so that when the blank is bent into the form of a cylinder the end strips and 6 form continuous cylindrical supporting rings or strips which'will edectively resist the strains developed by centrifugal force when the wheel is driven at a lu h rate out speed. .By ex tending the longitudinal slits so that "the front end. of each slit is inline transversely with the rear end of the next succeeding slit a straight transverse bendinay be given to themet'al between the ends oftheslitsln bringing the blades into proper angular relation to the end strips so that twisting and distortion or the metal tending to weaken or disrupt it is avoided. lBy arranging the longitudinal slits in the manner shown in Fig. 3, so that they extend from the end oi? a transverse slit into transverse alinement with the end of the neat succeeding slit, the transverse bend in the metal" between the blade and end strip maybe made substantially in line with the outer edge otthe blade, so'that-the outer edge or the blade is in the plane of the end stri s.

This provides a larger inlet opening for t e air entering the fan since the entrance end or? the blades is open. The" ends of thelongitudinal slits may. overlap somewhat if desired, and the transverse bend in the metal connecting the bladeswith; the end strip may be made so that the outer edges ot the blades are somewhat within the periphery ofthe end strips if desired, but

it is preterred to so make the bends that the inseam outer edges of the blades are substantially flush with the periphery of the end strips as shown. I

While it is preferred to employ the an rangement of longitudinal slits shown and described, and to so arrange the slits that the bend in the metal connecting the blades with the end strips is a substantially transverse bend. for the reasons given this ar rangement is not essential to the broader features of the invention, and may be will also be understood that the arrange blades lie within the plane of the end strips,

the invention, and that the arrangement oi? the slits and bends may be varied as found tions under which the wheel is to be used.

Having explained the nature and ob ect oi the invention, and specifically described bodied, what I claim; is z- 1. A centrifugal fan wheel comprising cylindrical metal sheet having a series oit parallel transverse slits and non-intersect ing slits extending longitudinally from the ends of the transverse slits within the edges oithe sheet to leave cylindrical marginal strips along the edges of the sheet, and having only the metal bounded by the transverse and longitudinal slits bent'atan angle to the end strips to form parallel blades integrally connected with theco-ntinuous cylindrical strips, substantially as described.

2. A centrifugal fan wheel comprising cylindrical metal sheet having a series ot transversely parallel slits and slits eat-end ing longitudinally from the ends of the transverse slits with their ends in transverse alinernent and separated by intervenin metal which is bent transversely to bring the blades-bounded by the slits into uniform an ular' relation to the strips between the st ges of the sheet and the longt t-udina-l slits, substantially as described.

,3. A centrifugal fan wheel comprising a sheet metal strip bent into cylindrical'torm and having transverse nal slits 3 extending from the ends of the slits 2 into transverse 'alinement to the succeeding slit 2 and separated therefrom by intervening metal .7 which is bent to bring the blades 4 bounded by the slits 2 and 3 into uniform an ular relation to the end strips 5' and 6, suistantially as described.

Witnesses:

Ngirrin l). MOPHAIL,

Greener E. STEBBINS.

varied and modified as found desirable. lt

ment or the slits and bends, so that the most desirable or best suited to the condi' one form oi? wheel in which it may be era--- slits 2 and longitudh BENJAMIN S. FOSS.

15 not essential to the broader features oi.

till

till 

